Air-compressor.



E. HILL.

AIR GOMPRESSQR. APPLICATION FILED MAY 5, 1913.

1,080,063, I Patented Dec. 2, 1913.

n W W W COLUMBIIA PLANOURAPH C0. WASHINGTON. b c.

- .Umrnn rarnnr orrron AIR- OM RESSOR Specification of Letters liatent Patented Dec. 2, 9 3- Application filed May 5, 1913. Serial No. 765,470.

T all whom it may concern.-

Be it known that I, EBENEZER HILL, a citizen of the United States, residing at Norwalk, in the county of Fairfield and State of Connecticut, have invented a new and useful Improvement in Air-Compressors, of which the following is a specification,

This invention relates to steam engine or electric motor driven air or gas compressors, and more particularly to those machines of this character which are designed to pump or compress comparatively large volumes of fluid to relatively high pressures.

A compressor which has been runin the usual way performing its days work is ordinarily stopped with air compressed to the standard working pressure in the storage reservoir and in the air duct leading from the compressor to the reservoir. Of course a compressor is liable to be stopped at any time hen Work ng al ne o While t er compressors are still at work maintaining the reservoir pressure, To start a compressor from rest again the working pressure requires of the prime motor not only the work of overcoming the back pressure in the air discharge pipe and in the air cylinder, but t e a ded eff rt of over ming the inertia of and causing the acceleration of the fly wheels, pistons, rods and all the other movable parts of the entire machine. These are economic factors of importance to be considered when the compressor is run by a steam engine and they become especially important factors when the motive power is derived from electric motor, as of course the armature of such a motor has but little torque when it first starts. It is thererange mechanism that an air or gas compressor can instantly by anyone be converted into a compressed air or gas engine for temporary use. To accomplish this end m n are provided whereby the actions of the ordinary valves of the air compressor can be reversed and the air under compression allowed to flow backward through the air cylinder,the intake air valves are tempo-rarily converted into exhaust valves and the discharge air valves are temporarily con-. verted into air pressure supply valves. To cause these valves to operate reversely small pistons are arranged in chambers adjacent to the ordinary compressor valves and by a suitably timed valve the compressed air is so directed that the pistons operate the air valves and cause them to admit air to and exhaust air from the compressor cylinder in such manner that the compressor piston is driven back and forth bythe air and becomes an element of power rather than a compressing element. a

The accompanying drawing shows a longitudinal sectionof an air compressor cylins der provided, according to this invention, with means whereby the piston may be caused to act as a motive part instead of a compression part. The details of the compressor, the air reservoir, and the engine or motor connections, forming no part of this invention, are not illustrated as they may be of any common design and arrangement and are perfectly understood by everyone at all familiar with power driven air come pressors.

The cylinder 1 has the usual piston 2 that by the rod 3 is connected in the usual way with the prime motor. The intake air pipe l opens into the port 5 which is provided with the usual inwardly opening air intake valve 6. This valve is normally held closed by the spring 7. The air discharge pipe 8 communicates with the port 9 and is designed to lead to the reservoir for the compressed air. The port 9 is controlled by the outwardly opening air discharge Valve 10 which is normally thrust to its seat by the spring 11. All of these parts are of the common form well known to those skilled in this art and normally, when the piston is reciprocated they act to draw in air from the intake and force it out under pressure through the discharge.

In a chamber 12 back of the air inletvalve is a piston 13 and in a chamber 14: back of the air discharge valve is a piston 15.

The chambers back of these pistons are connected by a branch pipe 16 that through the pipe 17 is connected with the interior of a valve chest 18. The valve chest shown contains a common form of slide valve 19 which is moved back and forth at the proper time by the rod 20 that is actuated by any well known mechanism. The valve chest has an exhaust opening 21 on one side and on the other side is connected by a pipe 22 with the air discharge pipe which leads to the storage reservoir. In this air pressure supply pipe 22 is a cook 23 and in the pipe 17 is a cook 24, while in the branch pipe 16 is a cook 25. The pipe 17 communicates with the underside of the slide valve and hence as the parts are shown in the drawing is open to the atmosphere. Then the slide valve is in the position shown there is no pressure in the pipes leading to the chambers back of the pistons. Under these conditions the pistons adjacent to the valves are not subjected to pressure, consequently have no efl'ect on the valves and allow them to operate normally for compressing air.

When the cooks 23, 2 1 and 25 are open, according to the movement of the slide valve, the air pressure is admitted to and exhausted from back of the pistons 13 and 15. The piston 15 adjacent to the air discharge valve 10 is exposed on its inside to the pressure in the port 9. Hence, when pressure is removed from back of the piston 15 by the exhaust of the pressure in the pipe 17 this piston will move out and carry the discharge valve with it, thus allowing the main air pressure to enter the cylinder. The efi'ect of this is to force the piston to the end of its stroke. During this period the air intake valve 6 is held closed by its spring because the pressure is at the same time exhausted back of the piston 13. The position of the slide valve then changes and air under pressure then enters through the pipes to the chambers back of the pistons 13 and 15 so as to force them in. This allows the valve 10 to close and opens the valve 6. The cylinder is then exhausted of air pressure through the air intake 4. Similar mechanism at the other end of the cylinderoperates reversely to that described and causes thepiston to make its return stroke. This action is kept up as long as the cocks in the pipes which lead from the air discharge pipe 8 to the valve pistons are opened. hen it is desired to discontinue the use of the compressor as an engine, after the moving parts have been set in motion, closing the cooks 23, 24 and 25 will cut ofi the pressure from back of the valve pistons 13 and 15 so that they will be inert as to any action on the valves 6 and 10. The piston 15 will then have pressure on its inside from the port 9 but as the cook 25 is now closed, the leakage of a little air past the piston 15, made purposely a little loose will balance the pressure so that this piston will not affect the normal action of the discharge valve. The machine is now in condition to operate as an air compressor.

By means of this simple mechanism and the manipulation of the cooks, the compressor can be instantly changed into. an air pressure engine for the purpose of assisting the starting of the machine and again changed back so that it will operate normally as a compressor after the inertia of rest has been overcome and the acceleration of the moving parts accomplished. This very much relieves the work of the prime engine or motor and conduces to economy and ease of action of the machine.

The invention claimed is:

1. The combination with an air compressor having intake and discharge valves, of pistons adapted to reverse the normal actions of said valves, means arranged to'conduct air under pressure to said pistons, and means arranged in said conductor to control the flow of air under pressure therethrough and the exhaust of air therefrom for the purpose of causing said pistons-to actuate said valves.

2. The combination with an air compressor having intake and discharge valves and springs normally holding said valves to their seats, of pistons adapted to open said valves against the actions of the springs, means adapted to conduct air under pressure from the discharge outlet of said compressor to the backs of the pistons, and means adapted to alternately permit the flow of air under pressure through said air conductor to the pistons and the exhaust of air from said conductor back of said pistons, whereby said pistons act to cause said valves to operate in a reverse manner to their normal operation.

3. The combination with an air compressor havingintake and discharge valves and springs arranged to normally close said valves, of pistons arranged to open said valves, a conductor leading from the dis charge from said compressor to the backs of said pistons, and a valve arranged in said conductor and adapted to alternately open and close said conductor so as to permit the passageof compressed air therethrough and the exhaust of air therefrom. V

4. The combination with an air compressor having intake and discharge valves and means for normally closing said valves, of

means arranged to opensaid valves, a con 5. The combination with an air compressor having intake. and discharge valves and springs for normally closing said valves, of hausting air pressure from back of the valve pistons adapted to open said valves, pipes pistons, and cocks arranged in said pipes for leading from back of said pistons to a valve controlling the flow of air therethrough.

chest, an air supply pipe leading from the EBENEZER HILL. discharge of said compressor to the valve Witnesses:

chest, a valve movable in the chest for alter- J. E. SLATER,

nately admitting air pressure to and ex- S. W. STEVENS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

